Fair testing and stubborn sets

Abstract

<p>Partial-order methods alleviate state explosion by considering only a subset of transitions in each constructed state. The choice of the subset depends on the properties that the method promises to preserve. Many methods have been developed ranging from deadlockpreserving to CTL ∗-and divergence-sensitive branching bisimilarity preserving. The less the method preserves, the smaller state spaces it constructs. Fair testing equivalence unifies deadlocks with livelocks that cannot be exited, and ignores the other livelocks. It is the weakest congruence that preserves whether the ability to make progress can be lost. We prove that a method that was designed for trace equivalence also preserves fair testing equivalence. We describe a fast algorithm for computing high-quality subsets of transitions for the method, and demonstrate its effectiveness on a protocol with a connection and data transfer phase. This is the first practical partial-order method that deals with a practical fairness assumption.</p>